We conducted a prospective study on the epidemiology and etiology of ILI in Leyte Island,Philippines.This study was conducted in the outpatient department of three health facilities:Leyte Provincial Hospital,Tacloban City Health Center,and Tanauan Rural Health Unit. Nasopharyngeal swab specimens were collected from
patients who attended three facilities with ILI. ILI was defined as fever 38 °C or feverish and either cough or nasal discharge being present.Details of the study design have been described previously